Illuminated panel



April 22, 1952 c. N- SHLENKER 21,594,081

ILLUMINATED PANEL Filed June 50, 1950 INVENTOR. Cl/@RL E5 MSHLENKEE.

A TTONEK `Patented pr. 22, 1.952

ILLUMINATED PANEL Charles N. Shlenker, New York, N. Y., assigner to Edwin A. Neugass, Port Chester, N. Y.

Application June 30, 1950, Serial No. 171,444

Claims.

This invention relates to improvements in illuminated panels, and particularly panels for aircraft instruments. It is designed to meet specifications unattainable in other panels, such as, specifications set forth in the United States Air Force-Navy Aeronautical Specifications.

It is an object of the present invention to provide a panel wherein the engraved characters are sharply defined without glare.

Another object is to provide a panel of the character described which gives a high contrast between the characters and the face of the panel, with the panel having a matte nish to diminish reflection of light from an oblique source in front thereof.

A further object of the invention is to provide a panel of the type described having a matte fmish, or low reflective surface, which resists scratching or scoring to thereby retain its light trapping characteristic indefinitely.

A still further object of this invention is to provide a laminated panel of the type described including a light transmitting lamination, a transilluminated, or translucent, lamination and an opaque outer lamination having a matte nish resisting abrasion and wherein openings are formed in the outer lamination to define characters and expose portions of the transilluminated or translucent intermediate lamination, with the outer and intermediate laminations providing a high contrast for improved Visibility of the characters.

Yet another object of the present invention is to provide a laminated panel having the characteristics referred to above, wherein the outer lamination is flexible to cushion the light transmitting lamination against shocks, retains splinters or chips that may be broken off the light transmitting lamination, and renders the panel more flame -resistant.

Various further and more specific objects, features and advantages will clearly appear from the detailed description given below, taken in connection with the accompanying drawing which forms a part of this specification and illustrates, merely by way of example, several embodiments of the invention.

The invention consists in such novel features, arrangements and combinations of parts as may be shown and `described in connection with the apparatus herein disclosed by way` of example only and as illustrative of preferred embodiments.

In the drawing:

Fig. 1 is a front elevation of a portion of a panel according to this invention;

Fig. 2 is a vertical sectional view taken on the line 2--2 of Fig. 1;

Fig. 3 is a Vertical sectional view, similar to Fig. 2, of a panel according to a modification of this invention;

Fig. 4 is a vertical sectional View, similar to Fig. 2, of a panel according to another modication of this invention; and

Fig. 5 is a vertical sectional View illustrating an` alternative manner of illuminating the panels according to this invention.

Referring to the drawing in detail, and initially to Figs. l and 2 thereof, a panel I0 is there shown which comprises a relatively thick sheet I I of clear, light-transmitting material, preferably plastic, such as for example methyl methacrylate; an intermediate relatively thin lamination, coating or film I2 of flexible translucent material, preferably of the class of polyvinyl or vinyl resins or materials, their polymers or copolymers, such as, for example, polyvinyl chloride using suitable plasticizers for flexibility or blended with nitrile rubbers for that purpose, vinyl chloride-acetate copolymers, polyvinylidene chloride, or vinyl chloride-vinylidene chloride copolymers; and an outer relatively thin lamination, coating or lm I3 of flexible opaque material, preferably of the class of polyvinyl or vinyl resins or materials, their polymers or copolymers, such as, for example, any of those mentioned above, and formed with a matte finish on its outer surface I4.

Translucent film I 2 is preferably colored while the opaque film I3 is preferably colored black to provide a high contrast. However, other colors, providing a suitable high contrast could be used.

The lamination may be performed by coating the surface of the sheets or layers with an adl hesive, and passing the superposed layers or sandwich through a set of rolls to squeeze out the excess adhesive, disperse it uniformly over the entire area, and help it to bond the layers together, or the lamination may be performed by bonding the several layers together with heat and pressure. As still another possibility, the lms I2 and I3 may be sprayed or brushed on in the form of a paint.

After the lamination of sheet II and films I2 and I3 is formed, the panel is fabricated therefrom by cutting it to suitable size and shape, and performing any other machine work that may be required, such as providing drilled holes for mounting. The characters are formed in the panel by suitable cutting away the black opaque film I3, as at I5 and I6, to expose the white trans-l Vlucent lm I2, therebeneath. When the panel is illuminated from the front, the characters will be easily visible by reason of the high contrast between the white letters and the black surface of the panel. Since the surface It has a matte iinish, that is a surface made up of a myriad of closely spaced peaks and valleys acting as light traps, there will be very little reflection olf the surface I 4 to disturb the high contrast.

It has been found that these peaks, forming the matte finish, are easily broken off, as by scratching or abrasion, when the outer lm I3 is formed of a rigid material. When the outer lm is formed of a flexible or elastometric material having a vinyl resin base in accordance with this invention, the resistance to the breaking off of these peaks is greatly increased and the panel retains its low reflective characteristic indelinitely. Y

The use of flexible material for films I2 and I3. in addition to retaining the matte linish of the outer surface I4, contributes several other noteworthy characteristics to the resulting panel. The exible films I2 and I3 protect the brittle methyl methacrylate forming sheet Ii from shocks, and act to retain any chips or splinters in place, if the sheet II is shattered. Further, the vinyl resins have the characteristic of being self-extinguishing, and therefore increase the flame resistance of the panel since the methyl methacrylate sheet II is only slow-burning.

The panel described above may be either edge illuminated, by a source of light embedded therein (Figs. l-Ll) or directed at the edges thereof, or by light projectedfrom the rear (Fig. 5).- As seen in Figs. 1 4, edge lighting of the panel', by a source of light embedded therein, may be provided by a panel light I of conventional construction, such as that manufactured by Grimes Manufacturing Company, Urbana, Ohio, under part No. A4295, which is disposed in an opening i8 formed through panel I0. Since the panel light is conventional, it will not be described in detail except to indicate that the sleeve I9 thereof is formed with cutouts 20 so that the light is directed radially into light transmitting sheet l I. Sheet II then transmits the light to the translucent sheet I2 to transilluminate the latter and a clear outline of the cutout characters I5 and It will be provided, free from glare.

It should be noted that if red bulbs are used in panel lights Il, or while bulbs with red lil-ters therearound, the light transmitted by the clear methyl methacrylate sheet II- will be red and the characters I5 and I6 will appear red when so transilluminated and white when light Il is extinguished.

In Fig. 5 an embodiment of the invention is illustrated in which the panel Ill, similar to that heretofore described, is illuminated by light projected against the rear surface of sheet Il byA a source 2l enclosed within a suitable casing 22 which may be shaped to direct the projected light uniformly against the back surface of' the panel. Here again, the light-transmitting sheet Il will transmit the light to the translucent sheet I2 to illuminate the characters defined by cutouts I5 and It formed in the outer opaque sheet I3. It hasV been found that with illumination from the rear, as in Fig. 5, the illumination of the characters with colored light, for example red light, lis best achieved by coloring sheet I.I red and utilizing a source 2| of white light. TheA sheet H2 then transmits red light tothe translucent sheet s0 that the characters will appear red when illuminated from the rear and white when the source 2| is extinguished.

In Fig. 3, a modification of the panel according to this invention is illustrated which includes the relatively thick sheet of light transmitting material II, and thin films of flexible vinyl I2 and I3 which are, respectively, translucent and colored white and opaque and colored black, as in the case of the panel, inA Figs. l and 2. Film I3 is provided with a matte finish I4" as before,

Vand sheet II' is edge-illuminated by the panel light Il', as illustrated, or may be illuminated from the. rear by a construction similar to that shown in Fig. 5. To define the characters, film I3 is formed with suitable cutouts I5 and I6. however, as distinguished from the embodiment in Figs. l and 2, sheet I2' extends forwardly into cutouts I5 and I6', as at 23 and 24, to lie flush with the matte finished outer surface i4.

In Fig. 4, still another modied embodiment of the invention is shown including a. light transmitting sheet II', translucent. ilexible sheet. l2 and opaque iiexible; sheet I3" having a matte surface i4. The characters are. defined by cutouts 15 and. It formed in the sheet i3", and the sheet I2 is extended through` these'cutouts beyond the surface I4'.", as atv 25 and 26,. to provide improved visibility of the characters when the panel is viewed from an angle. Since the raised characters, formed by extending sheet. I2 through the cutouts in sheet I3, are of an elastometric material they will resist abras-ion and rubbing off much. in the same manner as the matte finish of surface I4. Although the panel in Fig. 4 is shown as being edge lighted by a panel light I1", embedded therein, it is to be understood that the rear lighting. arrangement of Fig. 5 could be applied with; equal facility.

Although, in describing preferred embodiments of the invention, I haveV specified certain suitable materials and forms, it is to be understood that the panels of each modification embodying the invention have, in common, a sheet of light-transmitting material, a film or coating of lightly colored, translucent, elastometric or rubbery material and an outer film or coating of dark colored, opaque, elastometric or rubbery material formed with a matte finish and suitable cutouts exposing portions of the underlying Vtranslucent film. defining the desiredcharacters.

Having thus described the.- invention, it is` to be understood that changes and modifications, obvious to one skilled in the art, maybe eected in the illustrated embodiments within. the scope of the invention. which is intended to be defined by the appended claims.

What is claimed as new and desired to besecured by Letters Patent is:

l. A panel comprising a sheet of light transmitting material, a light colored translucent. film formed of an elastomeric and low-reflective flexible material and superposed on said sheet,. and a dark coloredV opaque film formed of an elastomeric and low-refiective flexible material and superposed on said translucentlm. said opaque nlm being formed with a roughened low-reflective outer surface and cut through to expose said translucent film for defining characters.

2. A panel comprising a sheet of light transmitting material, a light colored translucent film superposed on'said sheet, and` a dark colored opaque nlm superposed onA saidtranslucent film and having a roughened loW-reflectiveouter surface, both said. translucent and opaque films being formed of an elastomeric material having a 10W-reflective iiexible vinyl resin base, said opaque lm being cut through to expose said translucent lm for dening characters.

3. A panel according to claim 2; wherein said translucent film extends into the cut-out portions of isaid opaque lm to lie flush with said low-reilective outer surface at said cut-out portions.

4. An internally illuminating panel comprising a sheet of light transmitting material, a light colored translucent film formed of an elastomeric and low-reflective flexible material and superposed on said sheet, a dark colored opaque lm formed of jan elastomeric and low-reflective flexi# ble material and superposed on said translucent lm, said `opaque lm being formed with a roughened low-reective outer surface and having cut-out portions to expose said translucent film for vdefining characters, and means for illuminating said light transmitting sheet to trans'- illuminate the exposed translucent lm at said cut-out portions of the opaque lm.

5. A panel comprising a sheet of light transmltting material, a light colored translucent llm superposed on said sheet, and a dark colored REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 272,033 Edge Feb. 13, 1883 2,071,921 Dickson Feb. 23, 1937 2,298,365 Gits et al Oct.` 13, 1942 2,383,884 Palmquist Aug. 28, 1945 2,518,726 Shlenker Aug.4 15, 1950 OTHER REFERENCES Handbook of Plastics, Simonds, Weith, and Bigelow (page 440, paragraph 1) 2nd ed., Van Nostrand Co., N. Y. C.,`Oct. 1948. 

